Through the couplings at the tending-side end of different rolls in a paper machine, such as suction rolls and variable-crown rolls, and in paper finishing machines, such as variable-crown rolls or heated rolls in calenders, various media are passed into the rolls. These media include, for example, energy media, such as pressurized hydraulic fluid or compressed air, lubricating media, such as lubrication oil or water, and cleaning media, such as pressurized water. Further, in connection with the tending-side end of a roll, there may be various other couplings, such as a pressure equaling pipe and a lubricant exhaust pipe, setting and measurement apparatus for pressure and for positioning various members arranged inside the roll. For example, in the tending-side end of the forming suction rolls in the former of a paper machine, there are typically 6 large-diameter (e.g., diameter of about 60 mm) wash water couplings, 10 hydraulic couplings, an exhaust pipe for lubrication fluid at the tending side, a display of the meter for the vacuum level in the suction chamber, and devices for indicating the position of the vacuum box, as well as screws for regulating the positions of the edge seals of the suction chamber.
Depending on the extent of equipment, a suction roll in a paper machine includes, for example, the following couplings for the pipe system: at the tending side of the suction roll, a wash water coupling for the roll mantle, a wash water coupling for the suction box, a wash water coupling, 4 loading-air couplings, 3 locking-air couplings, input and outlet couplings for circulation lubrication of the bearing housings, and 2 grease lubrication couplings, and further, at the driving side, there are 2 grease lubrication couplings and input and outlet couplings for circulation lubrication of the bearing housings at the driving side.
In prior art suction rolls, the vacuum connection for the suction chamber has been arranged through the tubular shaft at the driving side.
In a manner known in the prior art, the couplings for media placed at the tending side of the rolls communicate with the supply pipes of the various media through metal-fabric reinforced hoses. The hoses have a length of about 1 to about 3 meters, and they are freely suspended. A particular problem is damage caused to the hoses in particular at the wet end of the paper machine. The hoses are curved, and chemicals adhere to the hose faces and harden the face of the hose. As a result of that, the face of the hose cracks, and the metal fabric in the interior of the hose is exposed. The metal fabric corrodes by the effect of the process waters, and there is an obvious risk of failure of the hoses. A damaged hose may cause dangerous situations, and the substance discharged from a hose has usually direct access to the wire circulation and causes even extensive disturbance in production and operation.
Failure of such hoses causes a considerable risk for safety at work, in particular if a highpressure hydraulic hose or hot-water hose is broken. Owing to this risk of damage, in many paper mills, the hoses are replaced, on the average, once a year for the sake of security. This causes a considerable expense both in the form of the installation work, the material, and in the form of standstills in operation. These long hoses often extend to the tending platforms and thus, cause a risk of tumbling and deteriorate the visual contact and the access to the servicing points. Also, damaged oil hoses cause a considerable risk for the environment because oil that enters into the wire circulation is likely to end up in a waterway. Attempts have been made to counteract damage to the various hoses by means of various fixing means and connecting pieces which keep the hoses apart from one another and thus, reduce the risk of damage arising from rubbing of the hoses against one another.
In prior art coupling arrangements for the tending-side ends of the rolls in paper machines, the confusion of the couplings is also a drawback, which confusion is an obvious drawback both in view of the operation and from an aesthetic point of view. A further drawback is the differences between different couplings and the resulting complication and high cost of the spare parts system and maintenance.
In a manner known from the prior art, in calenders for paper, on the cylindrical coupling part at the tending-side end of the calender rolls, a hood-like shield casing has been used, but this casing has not been sealed in any way, nor have the various problems mentioned above and related to the coupling hoses been solved by means of this protective casing.